From 9b0369c773c1d350a05435d8d3ec4e954828fb82 Mon Sep 17 00:00:00 2001 From: Chris Moore Date: Mon, 27 Feb 2012 04:19:32 -0800 Subject: [PATCH 1/5] Refactor SelectCoinsMinConf() and add unit tests. AvailableCoins() makes a vector of available outputs which is then passed to SelectCoinsMinConf(). This allows unit tests to test the coin selection algorithm without having the whole blockchain available. --- src/test/wallet_tests.cpp | 256 ++++++++++++++++++++++++++++++++++++++ src/wallet.cpp | 102 ++++++++------- src/wallet.h | 33 ++++- 3 files changed, 343 insertions(+), 48 deletions(-) create mode 100644 src/test/wallet_tests.cpp diff --git a/src/test/wallet_tests.cpp b/src/test/wallet_tests.cpp new file mode 100644 index 0000000000..705609464a --- /dev/null +++ b/src/test/wallet_tests.cpp @@ -0,0 +1,256 @@ +#include + +#include "main.h" +#include "wallet.h" + +// how many times to run all the tests to have a chance to catch errors that only show up with particular random shuffles +#define RUN_TESTS 100 + +// enables tests which currently fail, due to code which tries too hard to avoid sub-cent change +// #define STRICT + +using namespace std; + +BOOST_AUTO_TEST_SUITE(wallet_tests) + +static CWallet wallet; +static vector vCoins; + +static void add_coin(int64 nValue, int nAge = 6*24, bool fIsFromMe = false, int nInput=0) +{ + static int i; + CTransaction* tx = new CTransaction; + tx->nLockTime = i++; // so all transactions get different hashes + tx->vout.resize(nInput+1); + tx->vout[nInput].nValue = nValue; + CWalletTx* wtx = new CWalletTx(&wallet, *tx); + delete tx; + if (fIsFromMe) + { + // IsFromMe() returns (GetDebit() > 0), and GetDebit() is 0 if vin.empty(), + // so stop vin being empty, and cache a non-zero Debit to fake out IsFromMe() + wtx->vin.resize(1); + wtx->fDebitCached = true; + wtx->nDebitCached = 1; + } + COutput output(wtx, nInput, nAge); + vCoins.push_back(output); +} + +static void empty_wallet(void) +{ + BOOST_FOREACH(COutput output, vCoins) + delete output.tx; + vCoins.clear(); +} + +BOOST_AUTO_TEST_CASE(coin_selection_tests) +{ + static set > setCoinsRet; + static int64 nValueRet; + + // test multiple times to allow for differences in the shuffle order + for (int i = 0; i < RUN_TESTS; i++) + { + empty_wallet(); + + // with an empty wallet we can't even pay one cent + BOOST_CHECK(!wallet.SelectCoinsMinConf( 1 * CENT, 1, 6, vCoins, setCoinsRet, nValueRet)); + + add_coin(1*CENT, 4); // add a new 1 cent coin + + // with a new 1 cent coin, we still can't find a mature 1 cent + BOOST_CHECK(!wallet.SelectCoinsMinConf( 1 * CENT, 1, 6, vCoins, setCoinsRet, nValueRet)); + + // but we can find a new 1 cent + BOOST_CHECK( wallet.SelectCoinsMinConf( 1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); + + add_coin(2*CENT); // add a mature 2 cent coin + + // we can't make 3 cents of mature coins + BOOST_CHECK(!wallet.SelectCoinsMinConf( 3 * CENT, 1, 6, vCoins, setCoinsRet, nValueRet)); + + // we can make 3 cents of new coins + BOOST_CHECK( wallet.SelectCoinsMinConf( 3 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 3 * CENT); + + add_coin(5*CENT); // add a mature 5 cent coin, + add_coin(10*CENT, 3, true); // a new 10 cent coin sent from one of our own addresses + add_coin(20*CENT); // and a mature 20 cent coin + + // now we have new: 1+10=11 (of which 10 was self-sent), and mature: 2+5+20=27. total = 38 + + // we can't make 38 cents only if we disallow new coins: + BOOST_CHECK(!wallet.SelectCoinsMinConf(38 * CENT, 1, 6, vCoins, setCoinsRet, nValueRet)); + // we can't even make 37 cents if we don't allow new coins even if they're from us + BOOST_CHECK(!wallet.SelectCoinsMinConf(38 * CENT, 6, 6, vCoins, setCoinsRet, nValueRet)); + // but we can make 37 cents if we accept new coins from ourself + BOOST_CHECK( wallet.SelectCoinsMinConf(37 * CENT, 1, 6, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 37 * CENT); + // and we can make 38 cents if we accept all new coins + BOOST_CHECK( wallet.SelectCoinsMinConf(38 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 38 * CENT); + + // try making 34 cents from 1,2,5,10,20 - we can't do it exactly + BOOST_CHECK( wallet.SelectCoinsMinConf(34 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_GT(nValueRet, 34 * CENT); // but should get more than 34 cents + BOOST_CHECK_EQUAL(setCoinsRet.size(), 3); // the best should be 20+10+5. it's incredibly unlikely the 1 or 2 got included (but possible) + + // when we try making 7 cents, the smaller coins (1,2,5) are enough. I'd hope to see just 2+5, but 1 gets included too + BOOST_CHECK( wallet.SelectCoinsMinConf( 7 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); +#ifdef STRICT + BOOST_CHECK_EQUAL(nValueRet, 7 * CENT); + BOOST_CHECK_EQUAL(setCoinsRet.size(), 2); +#else + BOOST_CHECK(nValueRet == 7 * CENT || nValueRet == 8 * CENT); + BOOST_CHECK(setCoinsRet.size() == 2 || setCoinsRet.size() == 3); +#endif + + // when we try making 8 cents, the smaller coins (1,2,5) are exactly enough. + BOOST_CHECK( wallet.SelectCoinsMinConf( 8 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK(nValueRet == 8 * CENT); + BOOST_CHECK_EQUAL(setCoinsRet.size(), 3); + + // when we try making 9 cents, no subset of smaller coins is enough, and we get the next bigger coin (10) + BOOST_CHECK( wallet.SelectCoinsMinConf( 9 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 10 * CENT); + BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); + + // now clear out the wallet and start again to test chosing between subsets of smaller coins and the next biggest coin + empty_wallet(); + + add_coin( 6*CENT); + add_coin( 7*CENT); + add_coin( 8*CENT); + add_coin(20*CENT); + add_coin(30*CENT); // now we have 6+7+8+20+30 = 71 cents total + + // check that we have 71 and not 72 + BOOST_CHECK( wallet.SelectCoinsMinConf(71 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK(!wallet.SelectCoinsMinConf(72 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + + // now try making 16 cents. the best smaller coins can do is 6+7+8 = 21; not as good at the next biggest coin, 20 + BOOST_CHECK( wallet.SelectCoinsMinConf(16 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 20 * CENT); // we should get 20 in one coin + BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); + + add_coin( 5*CENT); // now we have 5+6+7+8+20+30 = 75 cents total + + // now if we try making 16 cents again, the smaller coins can make 5+6+7 = 18 cents, better than the next biggest coin, 20 + BOOST_CHECK( wallet.SelectCoinsMinConf(16 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 18 * CENT); // we should get 18 in 3 coins + BOOST_CHECK_EQUAL(setCoinsRet.size(), 3); + + add_coin( 18*CENT); // now we have 5+6+7+8+18+20+30 + + // and now if we try making 16 cents again, the smaller coins can make 5+6+7 = 18 cents, the same as the next biggest coin, 18 + BOOST_CHECK( wallet.SelectCoinsMinConf(16 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 18 * CENT); // we should get 18 in 1 coin + BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); // because in the event of a tie, the biggest coin wins + + // now try making 11 cents. we hope for 5+6 but get 5+7 due to fear of sub-cent change + BOOST_CHECK( wallet.SelectCoinsMinConf(11 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); +#ifdef STRICT + BOOST_CHECK_EQUAL(nValueRet, 11 * CENT); +#else + BOOST_CHECK(nValueRet == 11 * CENT || nValueRet == 12 * CENT); +#endif + BOOST_CHECK_EQUAL(setCoinsRet.size(), 2); + + // check that the smallest bigger coin is used + add_coin( 1*COIN); + add_coin( 2*COIN); + add_coin( 3*COIN); + add_coin( 4*COIN); // now we have 5+6+7+8+18+20+30+100+200+300+400 = 1094 cents + BOOST_CHECK( wallet.SelectCoinsMinConf(95 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 1 * COIN); // we should get 1 bitcoin in 1 coin + BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); + + BOOST_CHECK( wallet.SelectCoinsMinConf(195 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 2 * COIN); // we should get 2 bitcoins in 1 coin + BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); + + // empty the wallet and start again, now with fractions of a cent, to test sub-cent change avoidance + empty_wallet(); + add_coin(0.1*CENT); + add_coin(0.2*CENT); + add_coin(0.3*CENT); + add_coin(0.4*CENT); + add_coin(0.5*CENT); + + // try making 1 cent from 0.1 + 0.2 + 0.3 + 0.4 + 0.5 = 1.5 cents + // we'll get sub-cent change whatever happens, so can expect 1.0 exactly + BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); + + // but if we add a bigger coin, making it possible to avoid sub-cent change, things change: + add_coin(1111*CENT); + + // try making 1 cent from 0.1 + 0.2 + 0.3 + 0.4 + 0.5 + 1111 = 1112.5 cents + BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); +#ifdef STRICT + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we hope for the exact amount +#else + BOOST_CHECK(nValueRet == 1 * CENT || nValueRet == 1111 * CENT); // but get a single 1111 cent coin +#endif + + // if we add more sub-cent coins: + add_coin(0.6*CENT); + add_coin(0.7*CENT); + + // and try again to make 1.0 cents, the new coins will be used to make 2.0 cents - leaving 1.0 cent change + BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); +#ifdef STRICT + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we hope for the exact amount +#else + BOOST_CHECK(nValueRet == 1 * CENT || nValueRet == 2 * CENT); // but get a bunch of sub-cent coins totalling 2 cents + BOOST_CHECK_GE(setCoinsRet.size(), 4); // 0.7 + 0.6 + 0.5 + 0.2 = 2.0 for example +#endif + + // run the 'mtgox' test (see http://blockexplorer.com/tx/29a3efd3ef04f9153d47a990bd7b048a4b2d213daaa5fb8ed670fb85f13bdbcf) + // they tried to consolidate 10 50k coins into one 500k coin, and ended up with 50k in change + empty_wallet(); + for (int i = 0; i < 20; i++) + add_coin(50000 * COIN); + + BOOST_CHECK( wallet.SelectCoinsMinConf(500000 * COIN, 1, 1, vCoins, setCoinsRet, nValueRet)); +#ifdef STRICT + BOOST_CHECK_EQUAL(nValueRet, 500000 * COIN); // we hope for the exact amount + BOOST_CHECK_EQUAL(setCoinsRet.size(), 10); // in ten coins +#else + BOOST_CHECK(nValueRet == 500000 * COIN || nValueRet == 550000 * COIN); // but get 50k too much + BOOST_CHECK(setCoinsRet.size() == 10 || setCoinsRet.size() == 11); // in 11 coins +#endif + + // if there's not enough in the smaller coins to make at least 1 cent change (0.5+0.6+0.7 < 1.0+1.0), + // we need to try finding an exact subset anyway + + // sometimes it will fail, and so we use the next biggest coin: + empty_wallet(); + add_coin(0.5 * CENT); + add_coin(0.6 * CENT); + add_coin(0.7 * CENT); + add_coin(1111 * CENT); + BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 1111 * CENT); // we get the bigger coin + BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); + + // but sometimes it's possible, and we use an exact subset (0.4 + 0.6 = 1.0) + empty_wallet(); + add_coin(0.4 * CENT); + add_coin(0.6 * CENT); + add_coin(0.8 * CENT); + add_coin(1111 * CENT); + BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); +#ifdef STRICT + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we hope for the exact amount + BOOST_CHECK_EQUAL(setCoinsRet.size(), 2); // in two coins 0.4+0.6 +#else + BOOST_CHECK_EQUAL(nValueRet, 1111 * CENT); // but since value of smaller coins < target+cent, we get the bigger coin again + BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); +#endif + } +} + +BOOST_AUTO_TEST_SUITE_END() diff --git a/src/wallet.cpp b/src/wallet.cpp index 4e3b559f6a..f7e931dbbb 100644 --- a/src/wallet.cpp +++ b/src/wallet.cpp @@ -889,7 +889,32 @@ int64 CWallet::GetImmatureBalance() const return nTotal; } -bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, set >& setCoinsRet, int64& nValueRet) const +// populate vCoins with vector of spendable (age, (value, (transaction, output_number))) outputs +void CWallet::AvailableCoins(vector& vCoins) const +{ + vCoins.clear(); + + { + LOCK(cs_wallet); + for (map::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it) + { + const CWalletTx* pcoin = &(*it).second; + + if (!pcoin->IsFinal() || !pcoin->IsConfirmed()) + continue; + + if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0) + continue; + + for (int i = 0; i < pcoin->vout.size(); i++) + if (!(pcoin->IsSpent(i)) && IsMine(pcoin->vout[i]) && pcoin->vout[i].nValue > 0) + vCoins.push_back(COutput(pcoin, i, pcoin->GetDepthInMainChain())); + } + } +} + +bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, vector vCoins, + set >& setCoinsRet, int64& nValueRet) const { setCoinsRet.clear(); nValueRet = 0; @@ -901,54 +926,32 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe vector > > vValue; int64 nTotalLower = 0; + BOOST_FOREACH(COutput output, vCoins) { - LOCK(cs_wallet); - vector vCoins; - vCoins.reserve(mapWallet.size()); - for (map::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it) - vCoins.push_back(&(*it).second); - random_shuffle(vCoins.begin(), vCoins.end(), GetRandInt); - - BOOST_FOREACH(const CWalletTx* pcoin, vCoins) - { - if (!pcoin->IsFinal() || !pcoin->IsConfirmed()) - continue; - - if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0) - continue; + const CWalletTx *pcoin = output.tx; - int nDepth = pcoin->GetDepthInMainChain(); - if (nDepth < (pcoin->IsFromMe() ? nConfMine : nConfTheirs)) - continue; - - for (unsigned int i = 0; i < pcoin->vout.size(); i++) - { - if (pcoin->IsSpent(i) || !IsMine(pcoin->vout[i])) - continue; - - int64 n = pcoin->vout[i].nValue; + if (output.nDepth < (pcoin->IsFromMe() ? nConfMine : nConfTheirs)) + continue; - if (n <= 0) - continue; + int i = output.i; + int64 n = pcoin->vout[i].nValue; - pair > coin = make_pair(n,make_pair(pcoin,i)); + pair > coin = make_pair(n,make_pair(pcoin, i)); - if (n == nTargetValue) - { - setCoinsRet.insert(coin.second); - nValueRet += coin.first; - return true; - } - else if (n < nTargetValue + CENT) - { - vValue.push_back(coin); - nTotalLower += n; - } - else if (n < coinLowestLarger.first) - { - coinLowestLarger = coin; - } - } + if (n == nTargetValue) + { + setCoinsRet.insert(coin.second); + nValueRet += coin.first; + return true; + } + else if (n < nTargetValue + CENT) + { + vValue.push_back(coin); + nTotalLower += n; + } + else if (n < coinLowestLarger.first) + { + coinLowestLarger = coin; } } @@ -1023,12 +1026,14 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe nValueRet += vValue[i].first; } +#ifdef DEBUG //// debug print printf("SelectCoins() best subset: "); for (unsigned int i = 0; i < vValue.size(); i++) if (vfBest[i]) printf("%s ", FormatMoney(vValue[i].first).c_str()); printf("total %s\n", FormatMoney(nBest).c_str()); +#endif } return true; @@ -1036,9 +1041,12 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe bool CWallet::SelectCoins(int64 nTargetValue, set >& setCoinsRet, int64& nValueRet) const { - return (SelectCoinsMinConf(nTargetValue, 1, 6, setCoinsRet, nValueRet) || - SelectCoinsMinConf(nTargetValue, 1, 1, setCoinsRet, nValueRet) || - SelectCoinsMinConf(nTargetValue, 0, 1, setCoinsRet, nValueRet)); + vector vCoins; + AvailableCoins(vCoins); + + return (SelectCoinsMinConf(nTargetValue, 1, 6, vCoins, setCoinsRet, nValueRet) || + SelectCoinsMinConf(nTargetValue, 1, 1, vCoins, setCoinsRet, nValueRet) || + SelectCoinsMinConf(nTargetValue, 0, 1, vCoins, setCoinsRet, nValueRet)); } diff --git a/src/wallet.h b/src/wallet.h index dfdb7b8257..b2e0e5260e 100644 --- a/src/wallet.h +++ b/src/wallet.h @@ -14,6 +14,7 @@ class CWalletTx; class CReserveKey; class CWalletDB; +class COutput; /** (client) version numbers for particular wallet features */ enum WalletFeature @@ -60,7 +61,7 @@ public: class CWallet : public CCryptoKeyStore { private: - bool SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, std::set >& setCoinsRet, int64& nValueRet) const; + void AvailableCoins(std::vector& vCoins) const; bool SelectCoins(int64 nTargetValue, std::set >& setCoinsRet, int64& nValueRet) const; CWalletDB *pwalletdbEncryption; @@ -112,6 +113,8 @@ public: // check whether we are allowed to upgrade (or already support) to the named feature bool CanSupportFeature(enum WalletFeature wf) { return nWalletMaxVersion >= wf; } + bool SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, std::vector vCoins, std::set >& setCoinsRet, int64& nValueRet) const; + // keystore implementation // Generate a new key CPubKey GenerateNewKey(); @@ -602,6 +605,34 @@ public: }; + + +class COutput +{ +public: + const CWalletTx *tx; + int i; + int nDepth; + + COutput(const CWalletTx *txIn, int iIn, int nDepthIn) + { + tx = txIn; i = iIn; nDepth = nDepthIn; + } + + std::string ToString() const + { + return strprintf("COutput(%s, %d, %d) [%s]", tx->GetHash().ToString().substr(0,10).c_str(), i, nDepth, FormatMoney(tx->vout[i].nValue).c_str()); + } + + void print() const + { + printf("%s\n", ToString().c_str()); + } +}; + + + + /** Private key that includes an expiration date in case it never gets used. */ class CWalletKey { From e333ab56d5b9fd6b0510ef6b98caa8bfc5059082 Mon Sep 17 00:00:00 2001 From: Chris Moore Date: Sat, 7 Apr 2012 10:52:40 -0700 Subject: [PATCH 2/5] Move the random_shuffle call back into SelectCoinsMinConf() so we can unit test it. --- src/wallet.cpp | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/wallet.cpp b/src/wallet.cpp index f7e931dbbb..36dbe7aeb1 100644 --- a/src/wallet.cpp +++ b/src/wallet.cpp @@ -926,6 +926,8 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe vector > > vValue; int64 nTotalLower = 0; + random_shuffle(vCoins.begin(), vCoins.end(), GetRandInt); + BOOST_FOREACH(COutput output, vCoins) { const CWalletTx *pcoin = output.tx; From 4ce190a0157837df9a4a804f8e3f2941d1ffacf5 Mon Sep 17 00:00:00 2001 From: Chris Moore Date: Sat, 7 Apr 2012 10:55:03 -0700 Subject: [PATCH 3/5] Test that the coin selection code is suitably random, and add tests re. sub-cent change. --- src/test/wallet_tests.cpp | 72 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 71 insertions(+), 1 deletion(-) diff --git a/src/test/wallet_tests.cpp b/src/test/wallet_tests.cpp index 705609464a..dc8fe08439 100644 --- a/src/test/wallet_tests.cpp +++ b/src/test/wallet_tests.cpp @@ -9,8 +9,14 @@ // enables tests which currently fail, due to code which tries too hard to avoid sub-cent change // #define STRICT +// some tests fail 1% of the time due to bad luck. +// we repeat those tests this many times and only complain if all iterations of the test fail +#define RANDOM_REPEATS 5 + using namespace std; +typedef set > CoinSet; + BOOST_AUTO_TEST_SUITE(wallet_tests) static CWallet wallet; @@ -44,9 +50,15 @@ static void empty_wallet(void) vCoins.clear(); } +static bool equal_sets(CoinSet a, CoinSet b) +{ + pair ret = mismatch(a.begin(), a.end(), b.begin()); + return ret.first == a.end() && ret.second == b.end(); +} + BOOST_AUTO_TEST_CASE(coin_selection_tests) { - static set > setCoinsRet; + static CoinSet setCoinsRet, setCoinsRet2; static int64 nValueRet; // test multiple times to allow for differences in the shuffle order @@ -250,6 +262,64 @@ BOOST_AUTO_TEST_CASE(coin_selection_tests) BOOST_CHECK_EQUAL(nValueRet, 1111 * CENT); // but since value of smaller coins < target+cent, we get the bigger coin again BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); #endif + + // test avoiding sub-cent change + empty_wallet(); + add_coin(0.0005 * COIN); + add_coin(0.01 * COIN); + add_coin(1 * COIN); + + // trying to make 1.0001 from these three coins + BOOST_CHECK( wallet.SelectCoinsMinConf(1.0001 * COIN, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 1.0105 * COIN); // we should get all coins + BOOST_CHECK_EQUAL(setCoinsRet.size(), 3); + + // but if we try to make 0.999, we should take the bigger of the two small coins to avoid sub-cent change + BOOST_CHECK( wallet.SelectCoinsMinConf(0.999 * COIN, 1, 1, vCoins, setCoinsRet, nValueRet)); + BOOST_CHECK_EQUAL(nValueRet, 1.01 * COIN); // we should get 1 + 0.01 + BOOST_CHECK_EQUAL(setCoinsRet.size(), 2); + + // test randomness + { + empty_wallet(); + for (int i2 = 0; i2 < 100; i2++) + add_coin(COIN); + + // picking 50 from 100 coins doesn't depend on the shuffle, + // but does depend on randomness in the stochastic approximation code + BOOST_CHECK(wallet.SelectCoinsMinConf(50 * COIN, 1, 6, vCoins, setCoinsRet , nValueRet)); + BOOST_CHECK(wallet.SelectCoinsMinConf(50 * COIN, 1, 6, vCoins, setCoinsRet2, nValueRet)); + BOOST_CHECK(!equal_sets(setCoinsRet, setCoinsRet2)); + + int fails = 0; + for (int i = 0; i < RANDOM_REPEATS; i++) + { + // selecting 1 from 100 identical coins depends on the shuffle; this test will fail 1% of the time + // run the test RANDOM_REPEATS times and only complain if all of them fail + BOOST_CHECK(wallet.SelectCoinsMinConf(COIN, 1, 6, vCoins, setCoinsRet , nValueRet)); + BOOST_CHECK(wallet.SelectCoinsMinConf(COIN, 1, 6, vCoins, setCoinsRet2, nValueRet)); + if (equal_sets(setCoinsRet, setCoinsRet2)) + fails++; + } + BOOST_CHECK_NE(fails, RANDOM_REPEATS); + + // add 75 cents in small change. not enough to make 90 cents, + // then try making 90 cents. there are multiple competing "smallest bigger" coins, + // one of which should be picked at random + add_coin( 5*CENT); add_coin(10*CENT); add_coin(15*CENT); add_coin(20*CENT); add_coin(25*CENT); + + fails = 0; + for (int i = 0; i < RANDOM_REPEATS; i++) + { + // selecting 1 from 100 identical coins depends on the shuffle; this test will fail 1% of the time + // run the test RANDOM_REPEATS times and only complain if all of them fail + BOOST_CHECK(wallet.SelectCoinsMinConf(90*CENT, 1, 6, vCoins, setCoinsRet , nValueRet)); + BOOST_CHECK(wallet.SelectCoinsMinConf(90*CENT, 1, 6, vCoins, setCoinsRet2, nValueRet)); + if (equal_sets(setCoinsRet, setCoinsRet2)) + fails++; + } + BOOST_CHECK_NE(fails, RANDOM_REPEATS); + } } } From d650f96d5f48a9cc458af9ef644f57973ca7f48b Mon Sep 17 00:00:00 2001 From: Chris Moore Date: Sat, 7 Apr 2012 12:45:39 -0700 Subject: [PATCH 4/5] Preserve the shuffled order of coins with equal value to give more randomized coin selection. --- src/wallet.cpp | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/src/wallet.cpp b/src/wallet.cpp index 36dbe7aeb1..d190ad9242 100644 --- a/src/wallet.cpp +++ b/src/wallet.cpp @@ -17,6 +17,15 @@ using namespace std; // mapWallet // +struct CompareValueOnly +{ + bool operator()(const pair >& t1, + const pair >& t2) const + { + return t1.first < t2.first; + } +}; + CPubKey CWallet::GenerateNewKey() { bool fCompressed = CanSupportFeature(FEATURE_COMPRPUBKEY); // default to compressed public keys if we want 0.6.0 wallets @@ -980,7 +989,7 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe nTargetValue += CENT; // Solve subset sum by stochastic approximation - sort(vValue.rbegin(), vValue.rend()); + sort(vValue.rbegin(), vValue.rend(), CompareValueOnly()); vector vfIncluded; vector vfBest(vValue.size(), true); int64 nBest = nTotalLower; From 831f59ce8b179bd3180a73499da9b1dc1d5ecaeb Mon Sep 17 00:00:00 2001 From: Chris Moore Date: Thu, 12 Apr 2012 16:22:15 -0700 Subject: [PATCH 5/5] Fix coin selection to only include change when it's necessary. --- src/test/wallet_tests.cpp | 45 +++---------------- src/wallet.cpp | 93 +++++++++++++++++++++------------------ 2 files changed, 58 insertions(+), 80 deletions(-) diff --git a/src/test/wallet_tests.cpp b/src/test/wallet_tests.cpp index dc8fe08439..9b77b284e6 100644 --- a/src/test/wallet_tests.cpp +++ b/src/test/wallet_tests.cpp @@ -6,9 +6,6 @@ // how many times to run all the tests to have a chance to catch errors that only show up with particular random shuffles #define RUN_TESTS 100 -// enables tests which currently fail, due to code which tries too hard to avoid sub-cent change -// #define STRICT - // some tests fail 1% of the time due to bad luck. // we repeat those tests this many times and only complain if all iterations of the test fail #define RANDOM_REPEATS 5 @@ -109,15 +106,10 @@ BOOST_AUTO_TEST_CASE(coin_selection_tests) BOOST_CHECK_GT(nValueRet, 34 * CENT); // but should get more than 34 cents BOOST_CHECK_EQUAL(setCoinsRet.size(), 3); // the best should be 20+10+5. it's incredibly unlikely the 1 or 2 got included (but possible) - // when we try making 7 cents, the smaller coins (1,2,5) are enough. I'd hope to see just 2+5, but 1 gets included too + // when we try making 7 cents, the smaller coins (1,2,5) are enough. We should see just 2+5 BOOST_CHECK( wallet.SelectCoinsMinConf( 7 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); -#ifdef STRICT BOOST_CHECK_EQUAL(nValueRet, 7 * CENT); BOOST_CHECK_EQUAL(setCoinsRet.size(), 2); -#else - BOOST_CHECK(nValueRet == 7 * CENT || nValueRet == 8 * CENT); - BOOST_CHECK(setCoinsRet.size() == 2 || setCoinsRet.size() == 3); -#endif // when we try making 8 cents, the smaller coins (1,2,5) are exactly enough. BOOST_CHECK( wallet.SelectCoinsMinConf( 8 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); @@ -161,13 +153,9 @@ BOOST_AUTO_TEST_CASE(coin_selection_tests) BOOST_CHECK_EQUAL(nValueRet, 18 * CENT); // we should get 18 in 1 coin BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); // because in the event of a tie, the biggest coin wins - // now try making 11 cents. we hope for 5+6 but get 5+7 due to fear of sub-cent change + // now try making 11 cents. we should get 5+6 BOOST_CHECK( wallet.SelectCoinsMinConf(11 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); -#ifdef STRICT BOOST_CHECK_EQUAL(nValueRet, 11 * CENT); -#else - BOOST_CHECK(nValueRet == 11 * CENT || nValueRet == 12 * CENT); -#endif BOOST_CHECK_EQUAL(setCoinsRet.size(), 2); // check that the smallest bigger coin is used @@ -201,24 +189,15 @@ BOOST_AUTO_TEST_CASE(coin_selection_tests) // try making 1 cent from 0.1 + 0.2 + 0.3 + 0.4 + 0.5 + 1111 = 1112.5 cents BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); -#ifdef STRICT - BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we hope for the exact amount -#else - BOOST_CHECK(nValueRet == 1 * CENT || nValueRet == 1111 * CENT); // but get a single 1111 cent coin -#endif + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we should get the exact amount // if we add more sub-cent coins: add_coin(0.6*CENT); add_coin(0.7*CENT); - // and try again to make 1.0 cents, the new coins will be used to make 2.0 cents - leaving 1.0 cent change + // and try again to make 1.0 cents, we can still make 1.0 cents BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); -#ifdef STRICT - BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we hope for the exact amount -#else - BOOST_CHECK(nValueRet == 1 * CENT || nValueRet == 2 * CENT); // but get a bunch of sub-cent coins totalling 2 cents - BOOST_CHECK_GE(setCoinsRet.size(), 4); // 0.7 + 0.6 + 0.5 + 0.2 = 2.0 for example -#endif + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we should get the exact amount // run the 'mtgox' test (see http://blockexplorer.com/tx/29a3efd3ef04f9153d47a990bd7b048a4b2d213daaa5fb8ed670fb85f13bdbcf) // they tried to consolidate 10 50k coins into one 500k coin, and ended up with 50k in change @@ -227,13 +206,8 @@ BOOST_AUTO_TEST_CASE(coin_selection_tests) add_coin(50000 * COIN); BOOST_CHECK( wallet.SelectCoinsMinConf(500000 * COIN, 1, 1, vCoins, setCoinsRet, nValueRet)); -#ifdef STRICT - BOOST_CHECK_EQUAL(nValueRet, 500000 * COIN); // we hope for the exact amount + BOOST_CHECK_EQUAL(nValueRet, 500000 * COIN); // we should get the exact amount BOOST_CHECK_EQUAL(setCoinsRet.size(), 10); // in ten coins -#else - BOOST_CHECK(nValueRet == 500000 * COIN || nValueRet == 550000 * COIN); // but get 50k too much - BOOST_CHECK(setCoinsRet.size() == 10 || setCoinsRet.size() == 11); // in 11 coins -#endif // if there's not enough in the smaller coins to make at least 1 cent change (0.5+0.6+0.7 < 1.0+1.0), // we need to try finding an exact subset anyway @@ -255,13 +229,8 @@ BOOST_AUTO_TEST_CASE(coin_selection_tests) add_coin(0.8 * CENT); add_coin(1111 * CENT); BOOST_CHECK( wallet.SelectCoinsMinConf(1 * CENT, 1, 1, vCoins, setCoinsRet, nValueRet)); -#ifdef STRICT - BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we hope for the exact amount + BOOST_CHECK_EQUAL(nValueRet, 1 * CENT); // we should get the exact amount BOOST_CHECK_EQUAL(setCoinsRet.size(), 2); // in two coins 0.4+0.6 -#else - BOOST_CHECK_EQUAL(nValueRet, 1111 * CENT); // but since value of smaller coins < target+cent, we get the bigger coin again - BOOST_CHECK_EQUAL(setCoinsRet.size(), 1); -#endif // test avoiding sub-cent change empty_wallet(); diff --git a/src/wallet.cpp b/src/wallet.cpp index d190ad9242..127d580803 100644 --- a/src/wallet.cpp +++ b/src/wallet.cpp @@ -898,7 +898,7 @@ int64 CWallet::GetImmatureBalance() const return nTotal; } -// populate vCoins with vector of spendable (age, (value, (transaction, output_number))) outputs +// populate vCoins with vector of spendable COutputs void CWallet::AvailableCoins(vector& vCoins) const { vCoins.clear(); @@ -915,13 +915,51 @@ void CWallet::AvailableCoins(vector& vCoins) const if (pcoin->IsCoinBase() && pcoin->GetBlocksToMaturity() > 0) continue; - for (int i = 0; i < pcoin->vout.size(); i++) + for (unsigned int i = 0; i < pcoin->vout.size(); i++) if (!(pcoin->IsSpent(i)) && IsMine(pcoin->vout[i]) && pcoin->vout[i].nValue > 0) vCoins.push_back(COutput(pcoin, i, pcoin->GetDepthInMainChain())); } } } +static void ApproximateBestSubset(vector > >vValue, int64 nTotalLower, int64 nTargetValue, + vector& vfBest, int64& nBest, int iterations = 1000) +{ + vector vfIncluded; + + vfBest.assign(vValue.size(), true); + nBest = nTotalLower; + + for (int nRep = 0; nRep < iterations && nBest != nTargetValue; nRep++) + { + vfIncluded.assign(vValue.size(), false); + int64 nTotal = 0; + bool fReachedTarget = false; + for (int nPass = 0; nPass < 2 && !fReachedTarget; nPass++) + { + for (unsigned int i = 0; i < vValue.size(); i++) + { + if (nPass == 0 ? rand() % 2 : !vfIncluded[i]) + { + nTotal += vValue[i].first; + vfIncluded[i] = true; + if (nTotal >= nTargetValue) + { + fReachedTarget = true; + if (nTotal < nBest) + { + nBest = nTotal; + vfBest = vfIncluded; + } + nTotal -= vValue[i].first; + vfIncluded[i] = false; + } + } + } + } + } +} + bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfTheirs, vector vCoins, set >& setCoinsRet, int64& nValueRet) const { @@ -966,7 +1004,7 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe } } - if (nTotalLower == nTargetValue || nTotalLower == nTargetValue + CENT) + if (nTotalLower == nTargetValue) { for (unsigned int i = 0; i < vValue.size(); ++i) { @@ -976,7 +1014,7 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe return true; } - if (nTotalLower < nTargetValue + (coinLowestLarger.second.first ? CENT : 0)) + if (nTotalLower < nTargetValue) { if (coinLowestLarger.second.first == NULL) return false; @@ -985,46 +1023,19 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe return true; } - if (nTotalLower >= nTargetValue + CENT) - nTargetValue += CENT; - // Solve subset sum by stochastic approximation sort(vValue.rbegin(), vValue.rend(), CompareValueOnly()); - vector vfIncluded; - vector vfBest(vValue.size(), true); - int64 nBest = nTotalLower; + vector vfBest; + int64 nBest; - for (int nRep = 0; nRep < 1000 && nBest != nTargetValue; nRep++) - { - vfIncluded.assign(vValue.size(), false); - int64 nTotal = 0; - bool fReachedTarget = false; - for (int nPass = 0; nPass < 2 && !fReachedTarget; nPass++) - { - for (unsigned int i = 0; i < vValue.size(); i++) - { - if (nPass == 0 ? rand() % 2 : !vfIncluded[i]) - { - nTotal += vValue[i].first; - vfIncluded[i] = true; - if (nTotal >= nTargetValue) - { - fReachedTarget = true; - if (nTotal < nBest) - { - nBest = nTotal; - vfBest = vfIncluded; - } - nTotal -= vValue[i].first; - vfIncluded[i] = false; - } - } - } - } - } + ApproximateBestSubset(vValue, nTotalLower, nTargetValue, vfBest, nBest, 1000); + if (nBest != nTargetValue && nTotalLower >= nTargetValue + CENT) + ApproximateBestSubset(vValue, nTotalLower, nTargetValue + CENT, vfBest, nBest, 1000); - // If the next larger is still closer, return it - if (coinLowestLarger.second.first && coinLowestLarger.first - nTargetValue <= nBest - nTargetValue) + // If we have a bigger coin and (either the stochastic approximation didn't find a good solution, + // or the next bigger coin is closer), return the bigger coin + if (coinLowestLarger.second.first && + ((nBest != nTargetValue && nBest < nTargetValue + CENT) || coinLowestLarger.first <= nBest)) { setCoinsRet.insert(coinLowestLarger.second); nValueRet += coinLowestLarger.first; @@ -1037,14 +1048,12 @@ bool CWallet::SelectCoinsMinConf(int64 nTargetValue, int nConfMine, int nConfThe nValueRet += vValue[i].first; } -#ifdef DEBUG //// debug print printf("SelectCoins() best subset: "); for (unsigned int i = 0; i < vValue.size(); i++) if (vfBest[i]) printf("%s ", FormatMoney(vValue[i].first).c_str()); printf("total %s\n", FormatMoney(nBest).c_str()); -#endif } return true;